四舍五入函数---C#

#region 【四舍五入】函数
    /// <summary>
    /// 四舍五入函数
    /// </summary>
    /// <param name="value">要转化的数</param>
    /// <param name="decimals">小数位数</param>
    /// <returns>转化后的数</returns>
    private double RoundNew(string value, int decimals)
    {
        double dValue;

        if (value == "" || value == null)
        {
            value = "0";
        }

        try
        {
            dValue = Convert.ToDouble(value);
        }
        catch (Exception ex)
        {
            dValue = 0;
        }

        if (dValue < 0)
        {
            dValue =  Math.Round(dValue + 5 / Math.Pow(10, decimals + 1), decimals, MidpointRounding.AwayFromZero);
        }
        else if (dValue > 0)
        {
            dValue =  Math.Round(dValue, decimals, MidpointRounding.AwayFromZero);
        }
        return dValue;
    }
    #endregion